It's hard to blame him. Founded in 2007, the BROS has established a reputation in the local arts scene as a do-it-themselves theater ensemble guided by metal, beer and over-the-top silliness. The BROS' debut production was 2009's "Grundlehammer," a title that just about says it all.

But "Murdercastle," which opens Friday night at the Autograph Playhouse, is a jarring departure. Members of the cast and crew describe it as "dark" and "challenging," which seems appropriate since the plot centers on H. H. Holmes, one of America's first documented serial killers.

The title comes from the nickname given to Holmes' sprawling hotel, where the pharmacist-turned-murderer admittedly killed 27 people, mostly young women, in savage ways. Some say the death toll is inaccurately low, but no one argues Holmes' twisted brutality.

Writer and artistic director Jared Margulies says he was hesitant to tell Holmes' story — albeit a heavily fictionalized version of it — because of its gruesome nature. But rather than lightening the material, Margulies instead attacked it with gusto, creating a sinister tale of torture and madness set at the 1893 World's Fair in Chicago. At one point in the writing process, he secluded himself in a Western Maryland cabin for three "miserable" days, just to focus on writing ideas down.

"It remains to be seen whether my mother will like the show," Margulies, 27, said. "There were some people in BROS that were concerned about it, that the themes are too dark. Their biggest concern is not people that love the show, but people that come for the first time and think it's all we do.

"But it's no fun in doing this work if you don't challenge yourself as a company."

"Murdercastle," and its running time of two-and-a-half hours, is the BROS' most difficult challenge to date for reasons beyond the material. For one, it features the company's largest cast ever, of approximately 45 people. So BROS brought in Barbara Geary, a 52-year-old director living in Remington with decades of theater and acting training. Geary is the first director outside of the BROS' circle.

After seeing "Valhella" last May, Geary was impressed with the BROS' enthusiasm and genuine love of theater. For "Murdercastle," her goal was to elevate the cast's performances.

"I wanted to bring more acting chops, more levels in terms of the acting because this particular story really called for it," Geary said. "It'd be very easy to make it a gorefest. But when speaking with Jared, I understood from the get-go he did not want to go in that direction."

He also didn't want to turn Holmes into an over-sensationalized caricature of a killer.

"It's not a 'Sweeney Todd' glamorized [type of] show," Margulies said. "That was important to me. This was a real guy who did pretty terrible things."

If there's one aspect of "Murdercastle" not worrying the BROS, it's the music. DeCampos says this show is not a rock opera, but a metal opera. The majority of the music is "heavy," "technically angled" and riff-based.

"[The audience] is going to be bombarded with this deep, technically involved, crazy metal," DeCampos said. "It's going to be sensory overload, hopefully."

As it gets closer to opening night, some of the pressure shifts from the behind-the-scenes members to the cast, which ultimately has to bring the world of "Murdercastle" to life.

Moira Horowitz — the 28-year-old actress who plays Annie, the female lead — echoes DeCampos' nervousness. She expects that everyone in the audience will love parts of the show but she's unsure if everyone will love the show as a whole. But to Horowitz, the BROS' growth lies in changing the audience's preconceived notions of the ensemble.

"We don't want to be predictable," Horowitz, a Goucher alumna, said. "This is the best way we can prove to the greater audience that we're not one-trick ponies."

So how will Horowitz know she and the BROS achieved that goal?

"I will know I have done my job if people leave feeling a little bit sick," she said. "For my character, I really hope I can take people from tears to turned-on then back to tears again."

For a theater company that normally judges a show's success by the audience's smiles, hooting and fist-pumps, "Murdercastle" will be a test of whether or not BROS is capable of tackling more complicated and morally ambiguous stories.

"I want people walking out not just entertained," DeCampos said. "I want them to be almost confounded. I want them thinking about the show for days, trying to wrap their heads around what they just witnessed. We're very close to having that."

If you go

"Murdercastle" opens Friday and runs through May 25 at the Autograph Playhouse, 9 W. 25th St. Advanced tickets are $15; $20 at the door. Supporter tickets, for $25, are also available online. Call 202-355-8864 or go to baltimorerockopera.org.

John Marra's full-time job is an assistant community lot projects coordinator at Civic Works. But his second job, although he works for free, is quartermaster of puppets for the Baltimore Rock Opera Society.

The Rolling Stones announced a 15-city stadium tour Tuesday that will include a June 23 stop at Milwaukee's Summerfest. Tickets go on sale Monday, April 13 at 10 a.m. Go to summerfest.com for more information.